The records kept falling as July 2016 set new benchmarks for heat.
NASA said Aug. 16 that last month was not only the hottest July in recorded history, but also the hottest month known since temperature record-keeping began in 1880.
“It wasn’t by the widest of margins, but July 2016 was the warmest month since modern record keeping began in 1880,” Dr. Gavin Schmidt, director of the agency’s Goddard Institute for Space Studies, said. “It appears almost a certainty that 2016 also will be the warmest year on record.”
This July’s mean temperature was 0.1 degrees warmer than the previous July record holders that occurred in 2015, 2011, and 2009, according to NASA’s study.
The National Oceanic & Atmospheric Administration confirmed July’s status as the heat pacesetter for all months on Aug. 17.
NOAA said that July 2016 was 1.57 degrees Fahrenheit warmer than the average 20th century July and 0.11 degrees Fahrenheit above the previous record-holding month of July 2015.
That continued a decades-long trend for the month of the year that is the peak of summer in the northern hemisphere.
“July 2016 marks the 40th consecutive July with temperatures at least nominally above the 20th century average,” NOAA’s National Centers for Environmental Information said in a summary of the July temperature data. “July 1976 was the last time July global land and ocean temperatures were below average.”
The trend is not limited to every year’s July.
A new record for the warmest month of its kind has been set in each of the past ten months, according to NASA, dating back to October 2015.
NOAA pegged the hot streak at 15 record-setting months in a row.
The disparity is the result of differing methodologies used by the two agencies.
For the year of 2016 through the end of July, NOAA found that mean worldwide temperatures were 1.85 degrees Fahrenheit above the 20th century average.
The next-hottest January-July period came in 2014, when the average was 0.34 degrees F below this year’s measurement.
Both agencies use meteorological stations around the world to obtain air temperature data and ship- and buoy-based instruments to measure sea surface temperature. Antarctic research stations are also used to gather the data that underlies their monthly global temperature analysis reports.
A probe launched by NASA in 2006 has resumed communication with the agency after nearly 23 months of silence.
The STEREO-B spacecraft, which orbits the sun, lost contact with Earth on Oct. 1, 2014.
The Deep Space Network reestablished the link with STEREO-B at 6:21 pm EDT on Sunday.
The long interruption in communication with the spacecraft was most likely the result of a series of events that began with a test of its command loss timer. The device is a kind of automated switch that allows the spacecraft to recover after a hardware failure. It functions by re-setting the hardware if no commands are received for a certain period of time. In STEREO-B’s case, that re-set time was three days.
NASA explained a likely scenario for the communications failure at a website posted shortly after the loss of contact event and still available here. An animated film that provides one possible model for the probe’s communication failure is also available.
STEREO-B’s navigation system probably failed because it was unable to detect guide stars. This caused the probe’s high gain antenna to be pointed away from Earth, which meant that it could not receive a signal. The breakdown in the star tracking system was likely the result of a failed laser.
“Basically, we made a mistake in not accounting for one of those individual lasers failing,” Dr. Joseph Gurman, the STEREO project scientist at NASA’s Goddard Space Flight Center, said. “The data still looked good coming out of the unit as a whole even though one laser was bad. That got us into a situation where the spacecraft was getting bad navigational information.”
STEREO-B remains in an uncontrolled spin, a problem for which there is not currently enough power available to correct. The spacecraft obtains energy by means of solar arrays that extend out from its main section.
Gurman explained that NASA scientists are not sure how much power the probe’s batteries can produce or whether they can be fully re-charged.
“We don’t know if the batteries are damaged,” he said. “We know they can take some charge.”
Whether the spacecraft’s instrumentation is still functional is also unknown.
“I would say that we know nothing about the state of the instruments at this point,” Gurman said.
NASA will proceed cautiously to investigate the STEREO-B probe’s status. What Gurman and his colleagues want to avoid is any command that would return STEREO-B to an uncontrolled spin.
“We have an inertial problem that is giving bad information to the control system on the spacecraft,” he said. “We have to proceed in a step-by-step method.”
The first step will be to figure out the extent to which the probe has, to put it metaphorically, any gas in its tank.
“We have to heat up the probably frozen fuel in the fuel tank,” Gurman explained. “We can proceed from there to use the thrusters to right our attitude by using the autonomy software.”
Gurman is optimistic, though, about the prospects for obtaining more data about the sun from STEREO-B. NASA’s prior experience with another spacecraft that experienced a communication failure – the Solar and Heliospheric Observatory – indicates that instruments can survive with little or no damage, even in the cold of space, for quite some time.
“On SOHO, there were 12 principal investigator experiments,” Gurman said. “Only one mechanism in one telescope was damaged in such a way that we really couldn’t use the instrument. There was one instrument that suffered some degradation. That’s about it. We’re cautiously optimistic that we’ll be able to regain most of the scientific capability, if not all, that we had before.”
In any case, the STEREO mission formally ended eight years ago, so any data obtained from STEREO-B is beyond what was expected at the time of launch.
“Anything we get is gravy, to say the least,” Gurman said.
The probe’s twin, STEREO-A, also revolves around our closest star.
STEREO is an acronym that shortens the twin probes’ formal name – Solar Terrestrial Relations Observatories.